Contact breaker assemblies



June 2, 1970 w. L. FRY

CONTACT BREAKER ASSEMBLIES 2 Sheets-Sheet 1 Filed Aug. 6. 1968 III:

. l E NTOR WM)! ma 9 ATTORNEYS June .1970 w. L. FRY 3,515,834

CONTACT BREAKER ASSEMBLIES I Filed Aug. 6, 1968 2 Sheets-Sheet 2 INVENTOR X wma .37 BY ATTORNEYS United States Patent Office 3,515,834Patented June 2, 1970 3,515,834 CONTACT BREAKER ASSEMBLIES WilliamLawrence Fry, Birmingham, England, assiguor to Joseph Lucas (Industries)Limited, Birmingham, England, a British company Filed Aug. 6, 1968, Ser.No. 750,536 Claims priority, application Great Britain, Aug. 29, 1967,39,424/ 67 Int. Cl. H01h 1/00, 19/00 U.S. Cl. 200-466 Claims ABSTRACT OFTHE DISCLOSURE A contact breaker assembly for use in an ignitiondistributor includes a plate carrying a fixed contact. An insulatingheel member is mounted for pivotal movement relative to the plate and aconductive shell is engaged with the heel member. The conductive shellcarries the movable contact of the assembly and a spring urges the heelmember to pivot relative to the plate in a direction to engage themovable contact with the fixed contact.

This invenion relates to contact breaker assemblies, for use in ignitiondistributors, of the kind comprising a plate, a fixed contact carried bythe plate, an insulating heel member mounted for pivotal movementrelative to said plate, a movable contact carried by said heel memberand movable into and out of engagement with the fixed contact, and aspring urging said heel member to pivot in a direction to engage themovable contact with the fixed contact.

According to the invention in a contact breaker of the kind specifiedthe movable contact is secured to a conductive shell which is engaged asa snap fit with the insulating heel member.

One example of the invention is illustrated in the accompanying drawingswherein:

FIG. 1 is a sectional view of the movable contact arrangement of acontact breaker assembly,

FIG. 2 is a sectional view, not to scale, on the line 22 in FIG. 1,

FIG. 3 is an exploded perspective view of part of the arrangement shownin FIG. 1,

FIG. 4 is a part sectional plan view of an ignition distributorutilizing the contact breaker assembly shown in part in FIG. 1,

FIG. 5 is a side elevational view of the shell shown in FIG. 1, and,

FIG.6 is a view similar to FIG. 1 of a modification.

Referring to the drawings the contact breaker assem bly includes anarcuate plate (FIG. 4) having at one end thereof a hole. The plate 10 isengaged in use with the timing plate 31 of a distributor and a post 32extends upwardly from the timing plate 31 through said hole so as topivotally interconnect the plate 10 and the timing plate 31. The plate10 is formed intermediate its ends with an integral upstanding tab 10aon which is mounted the fixed contact 10b of the assembly.

Pivotally engaged with the post 32 and spaced from the arcuate plate 10by an insulating washer is a moulded insulating heel member 11. Themember 11 includes a body part 12 of generally rectangular cross sectionand at one end of the body part 12 is an integral cam follower 13 whichextends generally at right angles to the body portion 12. At its endremote from the cam follower 13 the body portion is formed integrallywith a pair of part circular resilient arms 15 which define a passage 16through which said post extends.

The body portion 12 of the member 11 carries a .resilient metal shell 17of generally inverted U-shaped configuration, the limbs 18, 19 of theshell being at right angles to the base 21 of the shell. The limb 18 ofthe shell 17 is extended to form an arm 22 and the movable contact 23 ofthe assembly is mounted at the free end of the arm 22. Trapped betweenthe limb 19 of the shell 17 and the body portion 12 of the member 11 isone end of a leaf spring 24, the other end of which is anchored to theplate 10, the spring 24 being arranged to urge the member 11 to pivot ina direction to engage the movable contact 23 with the fixed contact 10b.

The lower surface of the body portion 12 of the member 11 adjacent thearms 15 is cut away to define a shoulder 26 and the upper edge of theportion 12 above the shoulder 26 is chamfered to define a ramp surface27. Moreover at the end of the limb 18 remote from the arm 22 the shell17 includes an inwardly directed tag 28 which extends parallel with thebase 21 of the shell 17. Said one end of the leaf spring 24 is bent todefine a tag 24a which extends generally at right angles to theremainder of said one end of the spring 24, and the end of the limb 19of the shell 18 adjacent the cam follower 13 in use, is formed with anopen ended slot 19a equal in width to the width of the spring 24 and ofdepth slightly less than the thickness of the spring 24.

In order to assemble the shell 17 to the member 11, said one end of thespring 24 is engaged with the surface of the body portion 12 of themember 11 remote from the shoulder 26 and ramp surface 27 with the tag24a extending in contact with the cam follower 13, and the shell 18 isthen engaged with the body portion 12, with its limb 19 in facialcontact with said one end of the spring 24 and its tag 28 engaged withthe ramp surface 27. The shell is then urged downwardly in a directionto engage the base 21 of the shell 17 with the upper surface of the bodyportion 12. As the shell is so urged the tag 28 rides on the rampsurface 27 and the limbs 18, 19, of the shell 17 are flexed apart. Whenthe tag 28 reaches the shoulder 26 the limbs 18, 19 flex toward oneanother to engage the tag 28 with the shoulder 26 and the tag 24a of thespring 24 enters the slot 19a in the limb 19 of the shell 18. Thus theshell 17 is engaged as a snap fit with the member 11 and said one end ofthe spring 24 is trapped in position by the shell 17. The shell 17 isheld firmly in position in a vertical plane by engagement of the tag 28with the shoulder 26 while the base 21 of the shell 17 engages the uppersurface of the body portion 12, the shell 17 being located in ahorizontal plane by engagement of one edge of the limb 19 with the tag24a of the spring 24 which bears against the cam follower 13 while theopposite edge of the limb 18 engages a shoulder defined between the bodyportion 12 and one of the arms 15. The tag 24a is trapped against thecam. follower 13 by the shell 17 and thereby prevents movement of thespring 24 longitudinally relative to the heel 11, engagement of the tag24a in the slot 19a serving to prevent movement of the spring 24 in avertical plane relative to the shell.

When the contact breaker assembly is utilized in an ignition distributorthe fixed contact 10b is earthed through the plate 10 and the casing ofthe distributor, and the movable contact 23 is connected through theshell 17, the spring 24, and the primary winding of an ignition coil toone pole of a D.C. source, the other pole of which is earthed. Thus thecircuit through the primary winding of the ignition coil is made andbroken as the movable contact 23 is moved into and out of engagementwith the fixed contact 10b.

It will be appreciated that the shoulder 26 of the body portion 12 ofthe member 11 need not necessarily be formed in the lower surface of theportion 12 adjacent the cam follower 13, but could be formedintermediate the ends of the portion 12, in which case the ramp sur- 3face 27 and the tag 29 of the shell 17 would have to be positionedaccordingly.

In a modification shown in FIG. 5 the shoulders 26 and the surface 27are formed at the end of the body portion 12 of the member 11 adjacentthe cam follower 13, and the shell 17 is altered accordingly. Inaddition the tag 24a of the spring 24 is dispensed with and said one endof the spring 24 is formed with a square hole 33. The limb 19 of theshell is formed with an inwardly direeted square projection 29 by halfshearing the limb 19. When the shell 17 and member 11 are assembled theprojection 29 engages in the hole 33 to maintain the spring 24 inposition. One edge of the limb 19 engages the cam follower 13 while theopposite edge of the limb 18 engages said shoulder defined between theportion 12 and an arm 15 to locate the shell 17 in horizontal plane.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. A contact breaker assembly, for use in an ignition distributor,comprising,

a plate,

a fixed contact,

means mounting said fixed contact on said plate,

an insulating heel member,

means pivotally mounting said insulating heel member for pivotalmovement relative to said plate,

a movable contact,

means mounting said movable contact on said insulating heel member formovement into and out of engagement with the fixed contact by pivotalmovement of the insulating heel member relative to the plate,

a spring,

means engaging one end of said spring with said insulating heel member,and,

means engaging the other end of said spring with said plate, so thatsaid spring urges said insulating heel member to pivot in a direction,relative to said plate, to engage said movable contact with said fixedcontact,

wherein the improvement comprises,

a conductive shell,

means mounting said mova ble contact on said conductive shell, and

means on said conductive shell retaining said conductive shell engagedas a snap fit with the insulating heel member.

2. An assembly as claimed in claim 1 wherein one end of said spring issecured to the insulating heel member by trapping said one end betweenthe conductive shell and the insulating heel member.

3. An asembly as claimed in claim 2 wherein said one end of the springis bent to define a tag, and said conductive shell is formed with anopen ended slot, said tag engaged in said slot when shell and saidspring are engaged with said insulating heel member and thereby servingto locate said spring relative to said insulating heel member.

4. An assembly as claimed in claim 2 wherein said one end of said springis formed with a noncircular hole, and said conductive shell is formedwith a projection of correspondingly noncircular cross section, saidprojection engaged in said hole when said conductive shell and saidspring are engaged with said insulating heel member, and thereby servingtolocate said spring relative to said insulating heel member.

5. An assembly as claimed in claim 1 wherein said insulating heel memberand said conductive shell include mating surfaces which serve to locatesaid conductive shell in the desired position on the insulating heelmember.

References Cited UNITED STATES PATENTS 2,863,011 12/1958 Mallory 200-19X 3,003,043 10/1961 Meyer et a1. 200-19 X 3,033,947 5/1962 JohnsonZOO-19 X 3,037,096 5/1962 Clevenger n- 200--19 3,201,555 8/1965 Lacan eta1.

HERMAN O. JONES, Primary Examiner US. or. XR. 200-19

